You phone or email at around 6 weeks not before and they will give the first appointment at around 8 weeks. This is what we did. I phoned as soon as I discovered it and they told me to wait the 6 weeks before phoning
It was an online form to fill in rather than a call or an email and then I received an automated email that said they would contact me “shortly”
Once you self refer you will get a letter with the date of your midwife appointment around 8 weeks but yes you have to wait until you are around 6 weeks I believe
I emailed mine, took a day or two for response and I had a midwife within a week. Then I got the badger app details when I had my initial appointment at 8 weeks. May depend where you are based though!